"The River" is an important location and symbol in the Mnemosyne story. It is located in South Mundis, and is the basis of the small town of Riverbank. It is a location that appeared in the Four's Stasis World, and where they spent much of their time together. It represents the Four's home, and their youth, but above all it is a symbol of their friendship: ever-flowing, ever-changing, yet always there in some form.
Several important events take place at The River, most notably Thom's attack on his friends and the separation of the Four.